/**
 * This file is part of aionjp.
 *
 *  aionjp is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  aionjp is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with aionjp.  If not, see <http://www.gnu.org/licenses/>.
 */
package aionjp.network.crypt;

import java.io.IOException;
import java.util.logging.Logger;

/**
 * This class ...
 * 
 * @version $Revision: 1.3.4.1 $ $Date: 2005/03/27 15:30:09 $
 */
public class NewCrypt
{
	protected static Logger	_log	= Logger.getLogger(NewCrypt.class.getName());
	BlowfishEngine			_crypt;
	BlowfishEngine			_decrypt;

	/**
	 * @param blowfishKey
	 */
	public NewCrypt(byte[] blowfishKey)
	{
		_crypt = new BlowfishEngine();
		_crypt.init(true, blowfishKey);
		_decrypt = new BlowfishEngine();
		_decrypt.init(false, blowfishKey);
	}

	public NewCrypt(String key)
	{
		this(key.getBytes());
	}

	public static boolean verifyChecksum(byte[] raw)
	{
		return NewCrypt.verifyChecksum(raw, 0, raw.length);
	}

	public static boolean verifyChecksum(byte[] raw, final int offset, final int size)
	{
		// check if size is multiple of 4 and if there is more then only the
		// checksum
		if ((size & 3) != 0 || size <= 4)
		{
			return false;
		}

		long chksum = 0;
		long chksum2 = 0;
		int count = size - 4;
		long check = -1;
		int i;

		for (i = offset; i < count; i += 4)
		{
			check = raw[i] & 0xff;
			check |= raw[i + 1] << 8 & 0xff00;
			check |= raw[i + 2] << 0x10 & 0xff0000;
			check |= raw[i + 3] << 0x18 & 0xff000000;

			chksum ^= check;
		}

		chksum2 = check;
		check = raw[i] & 0xff;
		check |= raw[i + 1] << 8 & 0xff00;
		check |= raw[i + 2] << 0x10 & 0xff0000;
		check |= raw[i + 3] << 0x18 & 0xff000000;
		chksum2 ^= check;

		check = raw[i] & 0xff;
		check |= raw[i + 1] << 8 & 0xff00;
		check |= raw[i + 2] << 0x10 & 0xff0000;
		check |= raw[i + 3] << 0x18 & 0xff000000;

		// System.out.println("check = " + check + " chksum = " + chksum + "
		// chksum2 = " + chksum2);
		return 0 == chksum;
	}

	public static void appendChecksum(byte[] raw)
	{
		NewCrypt.appendChecksum(raw, 0, raw.length);
	}

	public static void appendChecksum(byte[] raw, final int offset, final int size)
	{
		long chksum = 0;
		int count = size - 4;
		long ecx;
		int i;

		for (i = offset; i < count; i += 4)
		{
			ecx = raw[i] & 0xff;
			ecx |= raw[i + 1] << 8 & 0xff00;
			ecx |= raw[i + 2] << 0x10 & 0xff0000;
			ecx |= raw[i + 3] << 0x18 & 0xff000000;

			chksum ^= ecx;
		}

		ecx = raw[i] & 0xff;
		ecx |= raw[i + 1] << 8 & 0xff00;
		ecx |= raw[i + 2] << 0x10 & 0xff0000;
		ecx |= raw[i + 3] << 0x18 & 0xff000000;

		raw[i] = (byte) (chksum & 0xff);
		raw[i + 1] = (byte) (chksum >> 0x08 & 0xff);
		raw[i + 2] = (byte) (chksum >> 0x10 & 0xff);
		raw[i + 3] = (byte) (chksum >> 0x18 & 0xff);
	}

	/**
	 * Packet is first XOR encoded with <code>key</code> Then, the last 4
	 * bytes are overwritten with the the XOR "key". Thus this assume that there
	 * is enough room for the key to fit without overwriting data.
	 * 
	 * @param raw
	 *            The raw bytes to be encrypted
	 * @param key
	 *            The 4 bytes (int) XOR key
	 */
	public static void encXORPass(byte[] raw, int key)
	{
		NewCrypt.encXORPass(raw, 0, raw.length, key);
	}

	/**
	 * Packet is first XOR encoded with <code>key</code> Then, the last 4
	 * bytes are overwritten with the the XOR "key". Thus this assume that there
	 * is enough room for the key to fit without overwriting data.
	 * 
	 * @param raw
	 *            The raw bytes to be encrypted
	 * @param offset
	 *            The begining of the data to be encrypted
	 * @param size
	 *            Length of the data to be encrypted
	 * @param key
	 *            The 4 bytes (int) XOR key
	 */
	public static void encXORPass(byte[] raw, final int offset, final int size, int key)
	{
		int stop = size - 8;
		int pos = 4 + offset;
		int edx;
		int ecx = key; // Initial xor key

		while (pos < stop)
		{
			edx = (raw[pos] & 0xFF);
			edx |= (raw[pos + 1] & 0xFF) << 8;
			edx |= (raw[pos + 2] & 0xFF) << 16;
			edx |= (raw[pos + 3] & 0xFF) << 24;

			ecx += edx;

			edx ^= ecx;

			raw[pos++] = (byte) (edx & 0xFF);
			raw[pos++] = (byte) (edx >> 8 & 0xFF);
			raw[pos++] = (byte) (edx >> 16 & 0xFF);
			raw[pos++] = (byte) (edx >> 24 & 0xFF);
		}

		raw[pos++] = (byte) (ecx & 0xFF);
		raw[pos++] = (byte) (ecx >> 8 & 0xFF);
		raw[pos++] = (byte) (ecx >> 16 & 0xFF);
		raw[pos++] = (byte) (ecx >> 24 & 0xFF);
	}

	public byte[] decrypt(byte[] raw) throws IOException
	{
		byte[] result = new byte[raw.length];
		int count = raw.length / 8;

		for (int i = 0; i < count; i++)
		{
			_decrypt.processBlock(raw, i * 8, result, i * 8);
		}

		return result;
	}

	public void decrypt(byte[] raw, final int offset, final int size) throws IOException
	{
		byte[] result = new byte[size];
		int count = size / 8;

		for (int i = 0; i < count; i++)
		{
			_decrypt.processBlock(raw, offset + i * 8, result, i * 8);
		}
		// TODO can the crypt and decrypt go direct to the array
		System.arraycopy(result, 0, raw, offset, size);
	}

	public byte[] crypt(byte[] raw) throws IOException
	{
		int count = raw.length / 8;
		byte[] result = new byte[raw.length];

		for (int i = 0; i < count; i++)
		{
			_crypt.processBlock(raw, i * 8, result, i * 8);
		}

		return result;
	}

	public void crypt(byte[] raw, final int offset, final int size) throws IOException
	{
		int count = size / 8;
		byte[] result = new byte[size];

		for (int i = 0; i < count; i++)
		{
			_crypt.processBlock(raw, offset + i * 8, result, i * 8);
		}
		// TODO can the crypt and decrypt go direct to the array
		System.arraycopy(result, 0, raw, offset, size);
	}
}
